USMLE Forum Archives - USMLE Step 1 - lep19
lep19
babbu5508 - 04-30-11 23:58
If the patient had been 85-years-old, and had involvement of the knee that had slowly developed over several days, which of the following types
of crystals would support the likely diagnosis in this case?
/ A. Negatively-birefringent needle-shaped crystals
/ B. Negatively-birefringent oval crystals
/ C. Negatively-birefringent rhomboidal crystals
/ D. Positively-birefringent needle-shaped crystals
/ E. Positively-birefringent rhomboidal crystals
babbu5508 - 04-30-11 23:58
If the patient had been 85-years-old, and had involvement of the knee that had slowly developed over several days, which of the following types
of crystals would support the likely diagnosis in this case?
/ A. Negatively-birefringent needle-shaped crystals
/ B. Negatively-birefringent oval crystals
/ C. Negatively-birefringent rhomboidal crystals
/ D. Positively-birefringent needle-shaped crystals
/ E. Positively-birefringent rhomboidal crystals
The correct answer and explanation will be available after you answer.
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#2
Re: lep19
babbu5508 - 05-15-11 01:21 My answer is: e.
The correct answer is E. Positively-birefringent rhomboidal crystals are classically found in cases of pseudogout. Pseudogout, or calcium pyrophosphate dihydrate (CPPD) disease, tends to affect older individuals, tends to affect the knee, wrist, shoulder, ankle, elbow, and hands, and may develop more insidiously. Nevertheless, the similarities between gout and pseudogout require aspiration of the joint for diagnosis.
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